STRUCTURAL INTERPRETATION AND RESERVIOR CHARACTERIZATION USING SEISMIC AND WELL DATA OF ZIARAT AREA, CENTRAL INDUS BASIN, PAKISTAN

Abstract

For evaluation of hydrocarbon potential in Ziarat area that lies in middle Indus basin this research is carried out. Ziarat is situated in western side of the Sulaiman Fold and Thrust Belt, east of Quetta Syntaxis The nearest town in the study area is Khost. Ziarat-1 was drilled in 2005 and was a commercial gas discovery from Chiltan Limestone, which encouraged exploration activities targeting deeper horizons for delineation of potential leads for prospects. The present study is conducted based on seismic and well data to achieve the aim of structural interpretation, petrophysical analysis along with seismic attributes and inversion. Assigned data was 2D seismic data that contains five seismic dip lines that are oriented in NS direction and two strike lines oriented in EW direction along with well log data. Seismic data was utilized for marking the horizons, three horizons are marked (Dungan Limestone, Goru and Chiltan horizons), and the type of structural trap are delineated. The structure has been interpreted is pop up structure. Chiltan (Jurassic) and Dungan Formation (Paleocene) are the primary reservoirs in this area but due to very low porosities they cannot be considered as a good reservoir. Seismic attributes have useful results, to recognize major lithological discontinuities, energy response and faults. Seismic inversion suggests that lithology of Dungan formation is limestone and impedance contrast variations suggests that there is a lithological change. Petrophysical analysis showed that Dungan formation have secondary porosity and tight reservoir conditions, but it is not of potentially sound enough to produce commercially hydrocarbons.